Gear pump



R. D. LEASE July 8, 1958 GEAR PUMP Filed March 7. 1955 4 Sheets-Sheet l INVENTOR. Pm. PH 0 L545:

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ArroR/wws United States Patent GEAR PUMP Ralph D. Lease, Royal Oak, Mich., assignor, by mesne assignments, to American Radiator & Standard Sanitary Corporation, New York, N. Y., a corporation of Delaware Application March 7, 1955, Serial No. 492,642

4 Claims. (Cl. 103-126) The present invention relates to a positive displacement rotary pump and is specifically concerned with a pump of this character which employs gears for the pumping members.

The gears in gear type pumps have heretofore been used mostly in pairs, along with a driving shaft, idler shaft, bearings, end plates and the pump body. The fluid inlet normally is on one side of the body and the fluid outlet is on the other side, resulting in a given fluid flow for a given set of gears operating at a given speed. When it is desired to obtain approximately double the fluid flow, the speed of the pump has to be doubled or the gear pumping members have to be doubled in diameter or in length, since the fluid first fills the spaces between the gear teeth as they separate on one side, and then it is carried around and squeezed out as the teeth mesh on the other side. Thus, the output is a direct function of the size and speed of. pump. 7 It is the primary object of the present invention to provide an improved gear pump in which the capacity is approximately doubled by a novel arrangement which is simple in construction and which can be easily and economically produced.

It is another object of the present invention to provide an improved gear pump of the foregoing character in which the capacity is approximately doubled by making use of three gears, one driven gear on either side of a driving gear, a simply constructed body, suction and discharge plates, and an outlet connection, such parts being constructed and arranged to provide an exceptionally efllcient unit.

It is still another object of the present invention to provide a pump characterized by its low cost of manufacture by making the suction end plate and the discharge end plate from simple, identical castings, and by attaching a simply constructed screen grille and screen onto the suction end plate and providing a discharge connection in conjunction with the drive shaft sleeve; all appropriately attached to the pump body along with the gears, drive shaft, idler shafts and bearings, thereby providing a compact fluid pump.

It is still another object of the present invention to provide a fluid pump which is constructed and arranged so that the fluid enters the pump body in an axial direction through the suction end plate by means of two suction passages leading into the suction cavities in said body, such fluid then being pumped into the discharge cavities in the body and passing out in the same axial direction through the discharge passages in the discharge end plate, and finally out the discharge connection, whereby such pump can be used in a vertical position submerged in the fluid with the suction end down, thus giving a greater suction head when the pump is in this operating position. p

, Other objects of this invention willappear in the following description and appended claims, reference being the three gears of the pump, with onlytwo of the gears' being shown in section;

Fig. 2 is an elevation of the suction end plate taken on the line 2--2 of Fig. l;

Fig. 3 is an elevation of the discharge end plate taken on the line 3-3 of Fig. 1;

Fig. 4 is a sectional view illustrating the suction and discharge cavities of the pump, taken on the lines 4-4 of Fig. 5;

Fig. 5 is a sectional view taken on the line 5-5 of Fig. l; and

Fig. 6 is a fragmentary end elevation of the suction side of the pump with a portion of the suction screen broken away.

Before explaining the present invention in detail, it is to be understood that the invention is not limited in its application to the details of construction and arrangement of parts illustrated in the accompanying drawings, since the invention is capable of other embodiments and of being practiced or carried out in various ways. Also, it is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation.

A pump embodying the present invention is essentially a positive displacement high head capacity type. The fluid is pumped by gears, one being the driving gear and two being idler gears mounted on opposite sides of the driving gear. These gears are nested within the pump body which has appropriate dividing walls extending to the driving gear, and the component parts provide two suction cavities and two discharge cavities so that approximately double the capacity is provided as compared to a conventional two gear type of pump while little additional enlargement of the pump is required.

The fluid is drawn into the suction cavities, with the idler gears then carrying approximately one-half the fluid between their teeth and the body walls to the discharge cavities and the driving gear carrying the other half between its teeth and the dividing walls also to the discharge cavities. From here the fluid is squeezed out into the discharge connection. 7

Referring now to the drawings a more detailed description of the pump will be given. The pump, identified generally by the reference number 10, has a hollow body member 12 containing two diametrically opposed suction cavities 14 and, 16 and two diametrically opposed discharge cavities 18 and 20, such cavities being circumferentially equidistantly spaced. On the suction or inlet end of the body member is a suction plate 22 which has two diametrically opposed inlet ports 24 and 26 which are axially aligned with the suction cavities 14 and 16. A strainer screen 28 is fitted over a strainer grill 3i), and the fitted parts are clamped by a strainer guard 32 against the inlet side of the suction plate by meansof a plurality of screws 34 which are threadedly connected to the body member 12.

As can be seen, the discharge plate 36 is identically the same in construction as the suction plate 22 and is on the discharge end of thebody member 12. Since the discharge plate 36 faces the opposite direction of the suction plate 22, its discharge ports 38 and 40 are in alternate quadrants from those of the suction plate, and therefore, are aligned with the discharge cavities 18 and 20 of the body member 12. p I

On the discharge side of plate 36 is an outlet connection 42. The latter is secured in place by a plurality of screws 44 which pass through the discharge plate 36 and are threadedly connected to the body member 12. The discharge ports 38 and 4d are in direct communication with the outlet 45 of the discharge connection 42 by means of the annular cavity 46 in the latter. I

A passageway 48 extends axially through the center of the discharge connection 4-2 through which a drive shaft 56 extends. The shaft 50 is journalled in the suction and discharge plates 22and 36 by a pair of bushings 52 and 54. Keyed to the drive shaft 50 for rotation therewith is a gear 56, preferably of the herringbone type so that end thrust in the pump will be avoided. The gear 56 is coaxially positioned within the body member 12 and its axis is in the same plane containing the dividing walls 53 and 60. As can be seen in Figure 5, these walls extend radially inward from the sides of the body member 12 and terminate in circular flanges 61 and 62' which are concentric with and have a radius slightly greater than the outer circle of the gear teeth of gear 56. Thus, the gear 56 and dividing walls 53 and 6% separate the hollow interior of the body member 12 into two halves.

Journaled in the suction and discharge plates 22 and 36 by bushings 63 are two idler shafts 64 and 66 carrying driven gears 63 and 76 which are in mesh with the driving gear 56. The driven gears 68 and '70 are in a plane containing the drive shaft 56/ and normal to the first named plane containing the dividing walls 555 u and 60. The sides of the body member 12 are cut out as at 72 so as to'receive therein the outer sides of the gears 64 and 66'. Thus, the interior of the body member 12 is divided into quadrants or four cavities, with cavities 14 and 16 being for suction purposes and cavities 18 and being for discharge purposes.

The embodiment of the invention illustrated in the drawings is intended to be used in a fluid drive system in which oil serves as the fluid. In this arrangement the pumped oil also serves as a lubricant between the various bushings and their associated driving or driven shafts.

The oil is pumped to the bushings from the discharge cavities 38 and through grooves formed in the inner faces of the suction and discharge plates. Thus, in the suction plate 22 the groove 74 leads from the discharge cavity 20 to the bushings 54 and 63 and the groove 76 leads from the discharge cavity 1% to the bushing 63. Likewise, in the discharge plate 36, the groove 78 leads to the bushings 52 and 63 and the groove 80 leads to the bushing 63. All of these bushings are grooved in the conventional manner to assist in distributing the oil over the entire surface of the various shaft journals.

The lubricant is discharged from the bushings 52, 63 at the suction side of the suction plate 22, and from the bushings 53, 63 through the passageway 48 and through the ducts 82 back to the sump from which the fluid is pumped.

In operation of the described embodiment, the drive shaft will be rotated in a clockwise direction as viewed in Fig. 5. The fluid will then be drawn into the body member 12 through the inlet ports 24 and 26 filling the suction cavities 14 and 16. Referring to Fig. 5, it can be seen that the fluid in the suction cavities flows therefrom by two separate paths. Part of the fluid in cavity 14 is caught between the teeth of gear 68 and the cut out portion 72 and is carried around to the discharge cavity 20, the remainder of the fluid is caught between the teeth of gear 56 and the circular flange 62 and is discharged into discharge cavity 18. In a similar manner, the fluid from suction cavity 16 is discharged partially into the discharge cavities 18 and 20 as shown by the arrows in Fig. 5. Thereafter, the fluid is forced from the cavities 18 and 20 through the annular cavity 46 and out the outlet 45.

From the foregoing it is believed clear that the disclosed embodiment of the invention has many novel and useful features. By virtue of the arrangement of the gears and the internal compartmentation, the capacity of the pump is approximately double that of a conventional pump of corresponding size. Furthermore, the arrangement shown wherein the fluid passes through the pump in an axial direction allows the suction end of the pump to be submerged in the fluid, if desired, thereby producinga maximum suction head. This arrangement also allows a suction screen to be attached at the suction end of the pump with a minimum increase in size and with a minimum increase in cost.

Other features of the pump are that it may be approximately cylindrical, permitting a wider choice of locations of the outlet connection, such that the pump may be submerged in the fluid to be pumped, thereby eliminating the necessity of suction piping, and improving the arrangement for piping the fluid from the discharge connection.

However, it is to be understood that the present invention is not limited in scope merely to the illustrated embodiment, since various other uses of the invention can be made. Thus, other applications can be made of the three gear arrangement where in the past two large gears or four of the size of the three gears would be necessary. One example of such other use is the ernployment of the pump in a position other than submerged. For this purpose the strainer parts at the suction side of the pump can be removed and a part similar to discharge connection 42 can be attached to the suction or inlet plate 22, after which the fluid can be conducted to the inlet side of the pump through a pipe. By virtue of this arrangement the pump can be located above the level of the fluid being pumped.

It should also be understood that the present invention is not limited to use in a fluid drive system-in which oil serves as the fluid. By suitable design of bearings and lubricating system the pump can be made to handle fluids other than oil.

Having thus described my invention, I claim:

1. A fluid pump comprising a hollow body member open at its ends; separate ported suction and discharge plates closing the opposite ends of said body member; a drive shaft journaled in said plates and carrying a drive gear within said body member; a plurality of driven gears each mounted in said body member in mesh with said drive gear, the axes of said driven gears being equidistantly spaced in a circle concentric with the axis of said drive shaft; dividing walls in said body member forming separate compartments in which said driven gears aremounted; the dividing walls extending inwardly toward said'drive gear and terminating in circular surfaces having approximately the same radius as the outer circle ofsaid drive gear; said driven gears extending between the drive gear and the opposite walls of the compartments in which the driven gears are mounted so as to divide the compartments into alternating suction and discharge cavities; suction ports extending through the suction plate into the suction cavities; discharge ports extending through the discharge plate into the discharge cavities; each of the three gears being of herringbone construction so as to minimize end' thrust on the pump parts.

2. A fluid pump comprising a hollow body member open at its ends; separate ported suction and discharge plates closing the opposite ends of said body member; a drive shaft journaled in said plates and carrying a drive gear within said body member; a plurality of driven gears each mounted in said body member in mesh with said drive gear, the axes of said driven gears being equidistantly spaced in a'circle concentric withthe axis of said drive shaft; dividing walls in said body member forming separate compartments in which said driven gears are mounted; the dividing walls extending inwardly toward said drive gear and terminating in circular surfaces having approximately the same radius as the outer circle of said drive gear; said driven gears extending between the drive gear and the opposite walls of the compartments in which the driven gears are mounted so as to divide the compartments into alternating suction and discharge cavities; suction ports extending through the suction plate into the suction cavities; discharge ports extending through the discharge plate into the discharge cavities; a grill member secured to the outer face of the suction plate; and

a strainer screen secured on the outer face of the grill member, whereby to permit the suction end of the pump to be submerged in fluid during operation.

3. A fluid pump comprising a hollow body member open at its ends; separate ported suction and discharge plates closing the opposite ends of said body member; a drive shaft journaled in saidplates and carrying a drive gear within said body member; a plurality of driven gears each mounted in said body member in mesh with said drive gear, the axes of said driven gears being equidistantly spaced in a circle concentric with the axis of said drive shaft; dividing walls in said body member forming separate compartments in which said driven gears are mounted; the dividing walls extending inwardly toward said drive gear and terminating in circular surfaces having approximately the same radius as the outer circle of said drive gear; said driven gears extending between the drive gear and the opposite walls of the compartments in which the driven gears are mounted so as to divide the compartments into alternating suction and discharge cavities; suction ports extending through the suction plate into the suction cavities; discharge ports extending through the discharge plate into the discharge cavities; a grill member including an annular section secured to the outer face of the suction plate, said grill member also including a series of spokes extending axially away from the annular section and then parallel to the suction plate; a strainer screen having a central section fitting against the outer faces of the spokes and an annular section fitting against the annular section of the grill member; an annular screen shield member having a first flange fitting against the annular screen section, and a second axially extending flange surrounding the screen central section;

and screws securing the shield member, screen, grill member, and suction plate onto the body member.

4. A fluid pump comprising a cylindrical hollow body member having a pair of internal coplanar dividing Walls extending radially inwardly and terminating at their inward ends in circular surfaces coaxial of said body member; plates closing the opposite ends of said body member; a drive shaft journaled in said plates coaxial of said circular surfaces; a drive gear carried on said drive shaft within the hollow body member and having an outer circle of substantially the same radius as said circular surfaces so that the dividing walls and drive gear divide the body member into two compartments; a pair of idler shafts journaled in said end plates on diametrically opposite sides of said drive shaft and in a plane normal to the plane containing said dividing walls; driven gears carried by said idler shafts in mesh with said drive gear and substantially in contact with the body member so as to divide the compartments into suction and discharge cavities; suction ports extending through one of said plates into the suction cavities; discharge ports extending through the other plate into the discharge cavities; and grooves formed in the inner surfaces of both plates, said grooves leading from the discharge cavities to the surfaces of the drive and idler shafts to permit flow of fluid to lubricate said shafts.

References Cited in the file of this patent UNITED STATES PATENTS 345,145 Jones July 6, 1886 557,123 Hall Mar. 31, 1896 679,169 Hunt July 23, 1901 2,256,743 Kleckner Sept. 23, 1941 2,354,992 Gottlieb Aug. 1, 1944 2,511,660 Wilson June 13, 1950 2,550,405 Crosby Apr. 24, 1951 2,571,377 Olah Oct. 16, 1951 2,681,621 Hedrnan June 22, 1954 2,687,693 Hudson Aug. 31, 1954 FOREIGN PATENTS 494,015 Belgium Mar. 15, 1950 

